[PSUBS-MAILIST] Group Help Request

Searching for Seadoo Scooter. Purchase one cut the kort nozzle off and
scrapp the rest. 
The swiming aid device of the serie and damage units are below 50 USD..

http://www.pbsboatstore.com/sea-doo.htm

http://www.ebay.de/itm/SeaDoo-Supercharged-Tauchscooter-Tauchen-Tauchsouter-/190947133334?pt=Tauchzubeh%C3%B6r&hash=item2c75560796


vbr carsten 
  

"Joe Perkel" <josephperkel at yahoo.com> schrieb: 
Jon,

The short answer is I dont know. But look at that Dutchman and his
simplistic ingenuity. Thats what Im hoping for out of this group as far
as materials and processes. Im ready to draw up whatever the result.
Consider that there are intrepid builders of all sorts of things
worldwide. Hovercrafters build large scale ducts for thier craft as a
example. I'll take a look there tomorrow.

How about half a kort??? A plug of some kind (construction grade foam
perhaps?) to build up a FRP shell over then mate two halves Revelle
model style??? Can this shape be hot wired?? What to use as a guide? I
have ideas and questions, but I need the shop wizards of the world to
come up with the process.

As for The other things, Im ready and willing. I like the thruster
because with my family and work time constraints, its not too much to
chew on. I can commit to small projects for now, bigger later as time
goes on.

What would you like to see done apart from the thrusters?

Joe



From: Jon Wallace <jonw at psubs.org>; 
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org>; 
Subject: Re: [PSUBS-MAILIST] Group Help Request 
Sent: Mon, Oct 28, 2013 12:33:12 AM 



What is the cost of having a true Kort nozzle machined by a CNC?  I
think a 30% improvement in thrust for $30 would be great but I suspect
machining a Kort is going to equate to many hundreds of dollars, if not
reaching beyond a thousand.  When I look at the Snoopy underwater videos
it is difficult to imagine a kort nozzle really making any difference in
the operational experience given that the motors are operating very
slowly and pushing Snoopy around at about 2 knots (estimated).  The
props are designed for power, but that's what we want underwater. 
True, a kort nozzle would increase that power but what is the return on
the cost?  In other words, on a road with a speed limit of 30mph and no
passing zones it doesn't matter whether you have a 1.6 liter or 5.4
liter engine under the hood does it?

Like Vance, I don't want to rain on the parade and I do "get it"
that the challenge of coming up with a "home-built" alternative can be
rewarding.  I just think that production cost will be the determining
factor on practical use.  Like going from T-Rex back to minn-kota, I
can't help but wonder if the ultimate conclusion will turn out to
be that the stock minn-kota's are good enough for 99.99% of our
applications.

I can think of many things that your CAD experience could offer to the
group if you are interested in providing some designs.  For example the
K350 plan modifications that have been talked about by a few people.  We
could really use help in that area.  

Jon



On 10/27/2013 6:20 PM, Joe Perkel wrote:

Alec,

I've gone round and round for the past two weeks in depth on the
issues of propulsion and have come full circle back to the trolling
motors. I was on hiatus for the discussion mentioned by Vance ref
contact with the manufacturer as I would have remembered that.

So, I'm with you on the prop and nozzle. While the 101's may
indeed have plenty of guts for the job as is, the Kort data shows a 30%
improvement in Bollard thrust at low speeds for any given prop diameter.
That and the added benefit of protecting the prop, are significant
enough reasons to forge ahead. This is actually good news, less work by
not mucking around with the guts of the motor.

You guys are the builders with recent hands on, I'm behind in the
trial and error business because I cant get started tinkering yet. But
as you well know, I developed CAD capability for this purpose only, so
time to put it to real use. Where I need help is deciding on materials
and manufacturing processes. I can give you guys the cutting files
needed to whittle a Kort out of a block of solid titanium, but that
would not be practical. That's my limitation and where hands on
experience counts.

Now these nozzles are reverse foils with coordinates in percent of
length. I can generate a NACA 4415 on my airfoil generator and transfer
that to the model.  I can give us accurate 3d models and eventually CNC
cutting files for whatever the group wants on these Minn Kotas, nozzles
and attachment hardware. I can do both Nozzles, Marin 19A, and or 37,
with the latter being optimized bi-directionally.

Finding something off the shelf would be ideal, but I suspect given the
nature of the business and the quote I recieved it would likely prove
problematic.

You need a new square tip prop to optimize the duct. I've had
custom props made for my boat in the past, so that should not prove
insurmountable. I should be able to do the prop as well. 

Can we post pictures on this forum?, I forget. It would be helpful to
point things out. If I could post pictures of the various exploded
diagrams, I can point to where I want dimensions with red arrows.
Eventually, I'll start a web-page.

So for now, I need some detail on the shaft and prop as is., what have
you done with that washer and where it is in the drive, as well as any
other modifications.

I think this is a decent group effort project, and one that can pay
dividends in the end.

Joe







 

-- 

Carsten Standfuß
Dipl.Ing.Schiffbau @ Meerestechnik
Heinrich Reck Str.12A
18211 Admannshagen

0172 8464 420
WWW.Euronaut.org
Carsten at euronaut.org
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